Wines that are meant to drink while young do great with a screw cap. Anything that I'd want to put in a cellar and age I'd want to have a natural cork.
The effects of micro-oxidization are definitely not the only change in taste that happen to an aging wine.
"Better" is a subjective term, and most people would actually prefer the fruitiness of a youthful wine. Heck, I know I do most of the time :) But there's something that develops with certain wines over time that I'm not just convinced that you can get with screw caps.
Maybe it's even part of some wine/wood interaction
Screw caps may be ok but they certainly look cheap.
I'm not convinced low-end corks are better than synthetic cork (in the case of some aging), and maybe the technology improves, leaving the solid corks to the expensive wines.
Supermarkets in France sell corks, I remember seeing them split by aging time, from 1,2 years up to around 20 years
People told them they were crazy, that the market thought screw tops were for cheap junk wine only, but they did it. And it worked. Now only bottles going to export markets use corks.
You lose the ritual of uncorking a bottle, but it's a lot more practical to open and there is no danger of the wine being corked.
"It takes at least 20 years for a tree to mature so it can be harvested"
If cork demand doubles tomorrow it means you will have to plant new trees and it will take at least 20 years before those trees are mature enough to be harvested.
A tree reaches maturity after ~25 years after planting, and the first harvest is usually low quality, so it doesn't bring money. After the first harvest it can be harvested every 9-10 years, and you can do so for hundred of years (a healthy cork oak can live for 5-600 years).
Cork does grow on trees, but slowly :).